. >> president obama vowed to find those responsible for the bombing. >> any responsible individuals, responsible groups will feel the full weight of justice. >> reporter: white house officials say they are treating the bombings as an act of terrorism. and the fbi is is appealing to marathon spectators, anybody that may have planted themselves at the finish line may have taken video, any audio or field pictures, the fbi wants to see those to unveil any evidence and clues to help them figure this out. in boston, susan mcginnis back to you. >> thank you for the live report. we are getting a sense of the scrambling that went on with boston law enforcement after the blast. here's a listen. >> this is an emergency, i need officers. >> you need to stay off the air. you need to stay off the air. make your way over there. off the air and make your way over there. >> besides the two bombs that went off, at least one other device was reported in the area and was safety disarmed. another device turned out not to be a bomb after all. a man was taken in for questioning shortly after the bombing. h